The invention relates to a valve with presetting facility, having a valve housing, which has an inlet nipple and an outlet nipple, a valve shaft, the closure member of which co-operates with a valve seat, and a cylindrical sleeve arranged concentrically about the valve shaft, which sleeve has a substantially closed base lying with its end face against a base face fixed with respect to the housing, spaced therefrom the valve seat, and in its circumferential wall at least one through-flow opening leading to the one nipple, and, in order to adjust a preset throttle that is formed by eccentrically arranged overlapping control openings in the end and base faces, the sleeve is arranged to be rotated and be fixed in position.
A valve of that kind in the form of a radiator valve is known from DE-PS 22 53 462. The presetting serves to limit the maximum flow of heating medium through the associated radiator. The two control openings are half-moon shaped openings in the base and in a plate set in the valve housing. The sleeve is coupled with a bushing that guides and seals the valve shaft, and can therefore be externally adjusted. Maximum flow volume is produced when the two control openings coincide with one another exactly. By rotating the sleeve the overlap region is reduced and thus a limit on the amount flowing through is set.
The plate set in the housing is required because it is difficult to create a half-moon shaped opening inside the valve housing. This is an expensive solution, however, because the plate has to be secured against rotation, and for that reason has a pin-like member which engages in an extra bore in the valve housing. In addition, it is difficult to set the desired flow rate exactly. That applies particularly when the flow rate is to be restricted to small amounts and in so doing the required setting tolerances are to be observed. These are as follows:
in the range from 0-10 kg/h the flow rate is +/-3 kg/h, PA1 in the range from 11-33 kg/h the flow rate is +/-6 kg/h.